Various technologies for detecting an object underwater have been proposed.
One of methods for detecting an underwater object is by using a sound wave, and an underwater object detector using a sound wave has been disclosed in Korean Patent Laid-Open Publication No. 1999-0078351 (publication date: 1999 Oct. 25).
However, in a region in which large noise occurs due to a strong tidal current, or a region in which water layers having temperature and salinity differences are mixed, it is difficult to detect the underwater object using the sound wave.
The other of methods for detecting an underwater object is by using an electromagnetic wave, and a mine detection system using an electromagnetic wave has been disclosed in U.S. Pat. No. 5,598,152 (issue data: 1997 Jan. 28).
However, since the mine detection system disclosed in U.S. Pat. No. 5,598,152 uses a method in which an automatic under vehicle (AUV) sequentially detects a mine while being moved, this method is suitable for detecting a stationary mine, but is unsuitable for detecting a moving object.